doc: update qat compression guide

Added limitations description for the QAT compression PMD.
Updated intermediate buffers description in qat.rst file.

Signed-off-by: Tomasz Jozwiak <tomaszx.jozwiak@intel.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>

diff --git a/doc/guides/compressdevs/qat_comp.rst b/doc/guides/compressdevs/qat_comp.rst
index 567a1fc..5631cb1 100644 (file)
--- a/doc/guides/compressdevs/qat_comp.rst
+++ b/doc/guides/compressdevs/qat_comp.rst
@@ -35,6 +35,10 @@ Limitations
 * Compressdev level 0, no compression, is not supported.
 * Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
 * No BSD support as BSD QAT kernel driver not available.
+* Number of segments in mbuf chains in the op must be <= RTE_PMD_QAT_COMP_SGL_MAX_SEGMENTS from the config file.
+* When using Deflate dynamic huffman encoding for compression, the input size (op.src.length)
+  must be < CONFIG_RTE_PMD_QAT_COMP_IM_BUFFER_SIZE from the config file,
+  see :ref:`building_qat_config` for more details.
 
 
 Installation

diff --git a/doc/guides/cryptodevs/qat.rst b/doc/guides/cryptodevs/qat.rst
index 3ca70bc..b079aa3 100644 (file)
--- a/doc/guides/cryptodevs/qat.rst
+++ b/doc/guides/cryptodevs/qat.rst
@@ -144,6 +144,8 @@ Quick instructions for QAT compressdev PMD are as follows:
        make
 
 
+.. _building_qat_config:
+
 Build Configuration
 ~~~~~~~~~~~~~~~~~~~
 
@@ -179,8 +181,8 @@ An extra (max_inflight_ops x 16) bytes per queue_pair will be used for every inc
 QAT compression PMD needs intermediate buffers to support Deflate compression
 with Dynamic Huffman encoding. CONFIG_RTE_PMD_QAT_COMP_IM_BUFFER_SIZE
 specifies the size of a single buffer, the PMD will allocate a multiple of these,
-plus some extra space for associated meta-data. For GEN2 devices, 20 buffers plus
-1472 bytes are allocated.
+plus some extra space for associated meta-data. For GEN2 devices, 20 buffers are
+allocated while for GEN1 devices, 12 buffers are allocated, plus 1472 bytes overhead.
 
 .. Note::